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Biomedical subjects

C Vigorito

Publications and source records attributed to C Vigorito.

At least 19 recordsLinked to original sources

Irbesartan effects on renal function in patients with renal impairment and hypertension: a drug-withdrawal study.

The blood-pressure lowering activity, tolerability, and safety of irbesartan was evaluated in 52 hypertensive patients with chronic renal insufficiency. After a 3-week placebo period, once-daily irbesartan was administered for 12 weeks at a daily dose of 150 mg titrated to 300 mg. A second, non-angiotensin-converting enzyme inhibitor, antihypertensive drug was added after 8 weeks as needed. Twenty-four-hour creatinine clearance was determined and renal clearance studies of inulin and para-aminohippurate were done in a subset of 11 patients. Trough sitting blood pressures were reduced at the end of the first week in all groups. At weeks 4, 8, and 12 the reductions in systolic blood pressure/diastolic blood pressure averaged -11.9/-8.7, -10.8/-9.4, and -14.7/-12.1 mm Hg in patients with mild renal insufficiency and -7.7/-6.3, -13.1/-11.8, and -14.1/-10.6 mm Hg in patients with moderate-to-severe renal insufficiency. Creatinine clearance, glomerular filtration rate, and effective renal plasma flow were stable. Irbesartan was withdrawn in only five patients because of adverse clinical or laboratory experience. Hyperkalemia (>6 mEq/l) requiring discontinuation of irbesartan occurred in only one patient. Once-daily irbesartan given as monotherapy at dose of 150-300 mg or in combination with other antihypertensive drugs is effective in reducing blood pressure in hypertensive patients with chronic renal disease. Irbesartan regimens are well tolerated in all groups. In addition, the blood pressure-lowering effect of irbesartan is accompanied by a significant reduction in proteinuria in patients with chronic renal insufficiency.

Adult↗

Effects of enalapril and isradipine alone and in combination on blood pressure, renal function and echocardiographic parameters in mild hypertension.

AIMS AND METHODS: A study was carried out to evaluate the influence of antihypertensive treatment with combined low doses of enalapril plus isradipine (5+5 mg daily) compared with those of either drug at a higher dose level (10 mg daily) by double-blind, three-way crossover study (balanced Latin square design) in 102 subjects (mean age 51.9 +/- 7.42 years) with essential hypertension. Left ventricular mass and function were evaluated by M-B mode echocardiography, renal function by glomerular filtration rate (GFR) and by serum and 24-h urinary Na+ and K+ during wash-out period and after 24 weeks of treatment. RESULTS: The supine blood pressure for subjects given placebo was 171/103 mmHg. After 24 weeks of treatment, systolic and diastolic supine blood pressure were significantly lower with 5 mg isradipine plus 5 mg enalapril (134/84 mmHg) than with 10 mg enalapril (137/84 mmHg) or with 10 mg isradipine (144/85 mmHg). Left ventricular posterior wall and septal thickness were significantly and similarly reduced in all groups. Left ventricular systolic and diastolic end diameters were not significantly changed. Left ventricular mass (LVM) was significantly reduced in E plus I group and enalapril group. GFR was not significantly altered. The 24-h urinary Na+ significantly increased with enalapril, more so than isradipine. The combination was tolerated better than either monotherapy. We observed no clinically significant changes in laboratory variables including blood lipoproteins. CONCLUSIONS: The combination of isradipine plus enalapril reduced blood pressure more effectively and was better tolerated than other drug alone. All three groups showed similar changes in echocardiographic indices and no change in renal function.

Analysis of Variance↗

Reversal of left ventricular hypertrophy following once daily administration of felodipine for two years to elderly subjects with isolated systolic hypertension.

Left ventricular mass sometimes decreases during the treatment of hypertension. In a two-year open study, we investigated the ability of extended release (ER) felodipine (5 or 10 mg), plus chlorthalidone (25 mg), given once daily, to reduce left ventricular mass in 84 elderly patients with isolated systolic hypertension. Drug dosage was determined in an initial stepped-care titration phase lasting six weeks. Mean systolic blood pressure decreased after two years of treatment with 5 or 10 mg of felodipine (p < 0. 001) and the left ventricular mass index decreased too (p < 0.0001). One or two weeks after withdrawal of therapies, blood pressure returned to pretreatment values. We concluded that left ventricular mass can be reduced in elderly patients with isolated systolic hypertension and ventricular hypertrophy who receive felodipine 5-10 mg once daily. This treatment was generally well tolerated.

Aged↗

Sympathetic deactivation by growth hormone treatment in patients with dilated cardiomyopathy.

AIMS: We examined the effects of growth hormone administration on the sympathetic nervous system in patients with idiopathic dilated cardiomyopathy. BACKGROUND: Growth factor therapy is emerging as a new potential option in the treatment of heart failure. Although growth hormone provides functional benefit in the short term, it is unknown whether it affects the sympathetic nervous system, which plays a role in the progression of heart failure. METHODS: Seven patients with idiopathic cardiomyopathy received 3 months treatment with recombinant human growth hormone (0.15-0.20 IU.kg-1.week-1). Standard medical therapy was unchanged. Myocardial norepinephrine release, both at rest and during submaximal physical exercise, plasma aldosterone, and plasma volume were measured before and after growth hormone treatment. Myocardial norepinephrine release was assessed from arterial and coronary venous plasma concentrations of unlabelled and tritiated norepinephrine and coronary plasma flow (thermodilution). RESULTS: Growth hormone induced a significant fall in myocardial norepinephrine release in response to physical exercise (from 180 +/- 64 to 99 +/- 34 ng.min-1; P < 0.05). Basally, plasma aldosterone was 189 +/- 28 and 311 +/- 48 pg.ml-1 in the supine and upright position, respectively, and fell to 106 +/- 16 (P < 0.01) and 182 +/- 29 pg.ml-1 (P < 0.05) after growth hormone therapy. Growth hormone increased plasma volume from 3115 +/- 493 ml to 3876 +/- 336 ml (P < 0.05), whereas serum sodium and potassium concentrations were unaffected. CONCLUSIONS: The data demonstrate that growth hormone administration to patients with idiopathic cardiomyopathy reduces myocardial sympathetic drive and circulating aldosterone levels. This neurohormonal deactivation may be relevant to the potential, long-term use of growth hormone in the treatment of patients with heart failure.

Adult↗

Metabolic and hemodynamic effects of peptide leukotriene C4 and D4 in man.

The time course of the effects of intravenous or intracoronary administration of peptide leukotrienes on metabolic parameters and on systemic and coronary hemodynamics was evaluated in 15 patients with normal coronary arteries. Peptide leukotriene C4 (2 nmol given as a bolus intravenous injection) induced an early fall (at 2 min) in mean arterial pressure (P < 0.02) associated with a rise in heart rate (P < 0.001) and in plasma levels of epinephrine (P < 0.05) and norepinephrine (P < 0.005), but without significant changes in coronary blood flow or coronary vascular resistance. Mean arterial pressure, heart rate, norepinephrine, and epinephrine returned to baseline values 10 min after leukotriene C4 administration. In contrast, at 10 min post leukotriene C4, with coronary blood flow and myocardial oxygen consumption unchanged, an increase in coronary vascular resistance (P < 0.05) and in myocardial oxygen extraction (P < 0.01) was observed, which returned to baseline values at 20 min post leukotriene C4. Peptide leukotriene D4 (3 nmol, given in the left coronary artery) induced an early (20 s) and transient fall in mean arterial pressure (P < 0.001) paralleled by a rise in heart rate and plasma levels of epinephrine and norepinephrine, all of which returned to baseline at 10 min. Coronary vascular resistance increased at 10 and 15 min (P < 0.02 and P < 0.05, respectively) and myocardial oxygen extraction at 15 min (P < 0.02). These results suggest that small doses of peptide leukotrienes induce both an early and transient fall in mean arterial pressure associated with secondary sympathoadrenergic activation, and a late increase in small coronary arteriolar resistance.

Adult↗

A preliminary study of growth hormone in the treatment of dilated cardiomyopathy.

BACKGROUND: Cardiac hypertrophy is a physiologic response that allows the heart to adapt to an excess hemodynamic load. We hypothesized that inducing cardiac hypertrophy with recombinant human growth hormone might be an effective approach to the treatment of idiopathic dilated cardiomyopathy, a condition in which compensatory cardiac hypertrophy is believed to be deficient. METHODS: Seven patients with idiopathic dilated cardiomyopathy and moderate-to-severe heart failure were studied at base line, after three months of therapy with human growth hormone, and three months after the discontinuation of growth hormone. Standard therapy for heart failure was continued throughout the study. Cardiac function was evaluated with Doppler echocardiography, right-heart catheterization, and exercise testing. RESULTS: When administered at a dose of 14 IU per week, growth hormone doubled the serum concentrations of insulin-like growth factor I. Growth hormone increased left-ventricular-wall thickness and reduced chamber size significantly. Consequently, end-systolic wall stress (a function of both wall thickness and chamber size) fell markedly (from a mean [+/-SE] of 144+/-11 to 85+/-8 dyn per square centimeter, P<0.001). Growth hormone improved cardiac output, particularly during exercise (from 7.4+/-0.7 to 9.7+/-0.9 liters per minute, P=0.003), and enhanced ventricular work, despite reductions in myocardial oxygen consumption (from 56+/-6 to 39+/-5 ml per minute, P=0.005) and energy production (from 1014+/-100 to 701+/-80 J per minute, P=0.002). Thus, ventricular mechanical efficiency rose from 9+/-2 to 21+/-5 percent (P=0.006). Growth hormone also improved clinical symptoms, exercise capacity, and the patients' quality of life. The changes in cardiac size and shape, systolic function, and exercise tolerance were partially reversed three months after growth hormone was discontinued. CONCLUSIONS: Recombinant human growth hormone administered for three months to patients with idiopathic dilated cardiomyopathy increased myocardial mass and reduced the size of the left ventricular chamber, resulting in improvement in hemodynamics, myocardial energy metabolism, and clinical status.

Adult↗

Reduced left ventricular mechanical efficiency in elderly patients with coronary artery disease.

We evaluated left ventricular (LV) mechanical efficiency in 23 elderly patients (mean age 67 +/- 2) with coronary artery disease (CAD) and in 22 patients younger than 65 years (mean age 49 +/- 8) with similar severity of CAD (2.4 +/- 0.8 and 2.2 +/- 0.8 vessels per patient, respectively) and history of myocardial infarction (34% and 41%, respectively). LV mechanical efficiency was calculated as the ratio of LV work per minute and myocardial O2 consumption. LV stroke volume was calculated from left ventriculography. Coronary blood flow was measured by thermodilution. Older patients had lower values of LV stroke volume (49 +/- 16 vs 73 +/- 16 mL, p < 0.005), ejection fraction (41 +/- 17 vs 58 +/- 17%, p < 0.05), LV stroke work (93 +/- 26 vs 131 +/- 41 g.m., p < 0.02) and LV work per minute (6.7 +/- 2.6 vs 9.3 +/- 2.7 kg.m./min, p < 0.05). Since myocardial O2 consumption was similar in the two groups, LV mechanical efficiency was lower in older CAD patients (16.2 +/- 15 vs 23.8 +/- 12%, p < 0.05). Thus, elderly patients with CAD show a reduced LV mechanical pump performance and efficiency, compared with younger patients with similar disease severity and history of myocardial infarction. These observations may contribute to understanding the higher frequency of congestive heart failure in elderly patients with CAD.

Adult↗

[Reduced endothelium-dependent peripheral vasodilation in the aged].

Endothelial dysfunction may be present years before the clinical manifestations of atherosclerosis, which is particularly frequent in the late decades of life. Therefore, we have evaluated the presence of endothelial dysfunction in the elderly by measuring, by echo-Doppler technique, the vasodilatation of brachial artery in response to the hyperemia following forearm occlusion and decompression, a response that is dependent on endothelial function. We studied 10 subjects > 65 years (mean 72 +/- 8) and 10 subjects < 65 years (mean 40 +/- 6) all without clinical signs and without risk factors for atherosclerosis. The increase in brachial arterial flow during reactive hyperemia was similar in the young and elderly subjects (152 +/- 74% vs 129 +/- 63%, NS). While in the young at peak hyperemia we found a significant increase in brachial artery diameter from 3.4 +/- 0.9 to 4.1 +/- 1.0 mm (p < 0.005), there was no significant change in the elderly (from 3.0 +/- 0.7 to 3.1 +/- 0.7 mm, NS). In both groups sublingual glyceryl trinitrate produced a significant increase in brachial artery diameter (from 3.0 +/- 0.7 to 3.5 +/- 0.8 mm in the elderly, p < 0.01, and from 3.4 +/- 0.9 to 3.9 +/- 0.9 mm in the young subjects, p < 0.01, NS among groups), showing the absence in the elderly of structural vascular changes potentially responsible for absence of dilatation. In conclusion, elderly subjects without clinical signs or risk factors for atherosclerosis have a vascular endothelial dysfunction that may play an important role in pathologic processes of the cardiovascular system in the late decades of life.

Adult↗

Echocardiographic vs hemodynamic monitoring during isometric exercise in patients with coronary artery disease.

BACKGROUND: Isometric exercise is able to induce myocardial asynergies in patients with coronary artery disease as demonstrated by noninvasive monitoring performed during stimulation. AIMS OF THE STUDY: In the present study, a combined echocardiographic and hemodynamic monitoring of left ventricular contractility has been conducted in order to verify, with invasive and noninvasive techniques, the ability of isometric exercise in inducing transient myocardial ischemic phenomena. METHODS: The study population was composed of 20 patients with angiographic evidence of significant coronary stenosis (> or = 50%), and 10 subjects with normal coronary angiograms. All 30 subjects admitted to the study underwent an isometric exercise stress during echocardiographic and hemodynamic monitoring of left ventricular contractility. RESULTS: Nine out of 20 patients with coronary disease showed regional asynergy during the test (Group I). The remaining 11 patients showed normal myocardial contractility (Group II). None of the 10 control subjects showed mechanical signs of ischemia during the test. Left ventricular end diastolic pressure significantly increased in both Group I (10 +/- 2 to 24 +/- 4 mmHg) and Group II (12 +/- 3 to 26 +/- 3 mmHg) (p < 0.01) while it remained unchanged in the control group (9 +/- 2 to 13 +/- 2 mmHg; p = NS); dp/dt increase (% basal) was significantly higher in the control group (45 +/- 6%) than in either Group I (25 +/- 3%) or Group II (26 +/- 3%) (p < 0.01). CONCLUSIONS: Isometric exercise was able to induce left ventricular asynergies due to regional myocardial ischemia. Hemodynamic contractility monitoring easily distinguished the control subjects from the patients with coronary disease but was not able to discriminate patients with handgrip-induced regional asynergy. Thus, the echocardiographic technique offers more detailed information about regional myocardial function than do the common hemodynamic contractility indexes.

Adult↗

Effects of intracoronary gallopamil on coronary hemodynamics and myocardial oxygen consumption in humans.

The response of coronary hemodynamics to the intracoronary (i.c.) bolus administration of gallopamil, 1.5 and 3.0 micrograms/kg, was evaluated in 14 patients with normal coronary arteries. Gallopamil, 3.0 micrograms/kg, induced a small and transient decrease in systolic and mean arterial pressure and a small increase in the preejection period. Coronary sinus blood flow increased significantly at 30 s (p less than 0.01) and returned to baseline 10 min after gallopamil administration. Coronary vascular resistance was still reduced at 10 min and returned to baseline at 15 min. Myocardial O2 consumption and extraction decreased significantly (p less than 0.01) at 30 s. While myocardial O2 consumption returned to baseline 15 min after gallopamil administration, myocardial O2 extraction was still significantly reduced at this time. Milder and more transient changes were observed after i.c. administration of the lower dose (1.5 micrograms/kg), and no significant changes were found after i.c. administration of saline. These data show that i.c. gallopamil, in patients with normal coronary arteries, induces direct, transient, and dose-related peripheral coronary vasodilation. The reduction of myocardial O2 consumption and extraction suggests a direct negative inotropic and metabolic effect of gallopamil.

Adult↗

Myocardial revascularization in women.

To compare the results of coronary artery bypass in women and men, we reviewed our experience from January 1976 through June 1989. During this period, 170 women with coronary artery disease but with no other cardiac abnormalities underwent coronary artery bypass. We compared this group with a group of 150 men, matching them according to age, presence of angina, extent of disease, and surgical treatment. Preoperative clinical features, surgical data, and early and late results were analyzed. The operative mortality was similar between groups (2.9% for women vs 2.6% for men). The women, however, were more frequently overweight (54% vs 15%; p <0.001) and more often had the following: diabetes mellitus (34% vs 20%; p <0.01), a coronary artery diameter of <1.8 mm (64% vs 29%; p <0.001), poor saphenous vein quality (50% vs 16%; p <0.001), and incomplete revascularization (20% vs 4%; p <0.001). After a mean follow-up of 6 years, the women also had a higher incidence of recent-onset myocardial infarction (31% vs 12%; p <0.001) and a greater tendency to be symptomatic (48% vs 19%; p <0.001). The 12-year cumulative survival rates were similar in both groups (76.2% for women vs 77.1% for men). According to logistic regression analysis of the significantly different variables, the only independent determinants of postoperative asymptomatic status were satisfactory coronary artery caliber, good saphenous vein quality, and complete revascularization. We conclude that poorer functional results after coronary artery bypass surgery in women may be caused by a poorer quality of revascularization, which in turn is a result of smaller coronary artery diameter, worse distal runoff, and less satisfactory vein quality.

Journal Article↗

Myocardial metabolism in insulin-deficient diabetic humans without coronary artery disease.

Eleven insulin-dependent diabetes mellitus (IDDM) patients with angiographically normal coronary arteries and a normal hemodynamic response to an echocardiographic-dipyridamole test and 12 normal controls were studied at rest and after atrial pacing simultaneously sampling arterial and coronary sinus blood. In IDDM patients, despite hyperglycemia [10.0 +/- 2.0 (SE) mmol/l], myocardial glucose uptake was slightly lower than in controls. This process was significantly activated in both groups during atrial pacing. The isotopically calculated net flux of lactate across myocardium, in agreement with the net balance value based on unlabeled lactate-pyruvate arteriovenous differences, showed a net uptake in controls (3.5 +/- 0.6 mumol.min-1.1.73 m-2) and a net release in IDDM (12.4 +/- 2.6; P less than 0.01). Atrial pacing stimulated lactate uptake in both groups. Myocardial uptake of ketone bodies was significantly higher in IDDM (37.0 +/- 6.3 mumol.min-1.1.73 m-2) than in controls (10.1 +/- 3.4 mumol.min-1.1.73 m-2; P less than 0.01). Free fatty acid uptake was also significantly greater in IDDM than in controls (44.1 +/- 7.0 vs. 24.1 +/- 5.1 mumol.min-1.1.73 m-2; P less than 0.01). Alanine and branched amino acids were released by diabetic but not by control hearts at rest. The normalization of blood glucose concentrations restored normal patterns of lactate and ketone body kinetics across diabetic myocardium. In conclusion, 1) at rest, myocardial lactate and amino acid uptake is markedly impaired in IDDM without coronary artery disease, and 2) the metabolic abnormalities of the diabetic myocardium are not a primary phenomenon but rather a consequence of hypoinsulinemia and hyperglycemia because insulin administration, resulting in euglycemia, restored normal patterns of cardiac metabolism.

Adult↗

Differences in blood pressure profile between young and elderly hypertensive patients.

We studied 40 subjects, 20 under 60 yrs old (10 normotensive and 10 hypertensive) and 20 over 60 yrs old (10 normotensive and 10 hypertensive). Each patient underwent a 24-hour ambulatory blood pressure monitoring (8:00 a.m. to 8:00 a.m.), by a noninvasive method using an ICR 5300 apparatus. Systolic blood pressure was significantly higher on random measurement and during the daytime in the older patients. Although comparison of the other parameters did not reveal significant differences, we noted a tendency to higher systolic values among the older group, and higher diastolic values in the younger one. The variability of the values was slightly higher, although not significantly, among the older patients. In both groups random systolic measurements, and in the younger group diastolic values as well, were significantly higher than mean 24 hour values. The incidence of abnormal systolic BP values ranged from 18.8% to 100% (mean 60.2% +/- 28.9) in younger hypertensives, and from 54% to 100% (mean 76.5% +/- 14.4) in older patients. The incidence of abnormal diastolic BP values ranged from 64.5% to 100% (mean 80.4% +/- 15.6) in younger patients and from 47.2% to 96% (mean 67.8% +/- 15.8) in older patients. The correlation between mean systolic and diastolic values recorded from 8:00 to 10:00 a.m., and mean 24-hour values was significant in young hypertensives, while in the older group there was a significant correlation only for diastolic BP. The lack of significance for systolic values is probably due to a greater variability in systolic pressure in elderly subjects during the morning.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Effects of aging and beta-adrenergic-blockade on standing-induced QT/QS2 changes.

In order to evaluate whether the changes in the electrical systole/electromechanical systole ratio (QT/QS2) may reflect the effects of beta-adrenergic stimulation on the heart, we studied the variations of this ratio induced by active standing. We studied 45 healthy volunteers aged 15 to 82 years, subdivided into three groups; Group 1 (mean age 22 +/- 4 years), Group 2 (mean age 44 +/- 6 years), and Group 3 (mean age 74 +/- 6 years). Fifteen subjects repeated the test after propranolol administration (0.1 mg/kg iv). Resting QT/QS2 ratio increased slightly, but not significantly, with age. Upright position significantly increased QT/QS2 ratio in all groups. Changes in heart rate (r = -.43), electromechanical systole (r = .55) and QT/QS2 were significantly correlated with age. Propranolol prevented the increase in QT/QS2 ratio induced by active standing. Therefore, QT/QS2 changes induced by standing are correlated with age and are inhibited or reduced by beta-blockade. QT/QS2 changes can be used to monitor adrenergic activity, even if their value is limited by the overlapping responses of the individual cases.

Adolescent↗

Relationship between QT interval duration and exercise-induced ventricular arrhythmias.

This study was performed to determine if QT prolongation before and during early exercise is related to the occurrence of exercise-induced ventricular arrhythmias (EIVA). EIVA occurred in 47 of 142 patients with angiographic evidence of coronary artery disease (CAD); no EIVA occurred among the 22 patients without CAD (OV). Resting QTc and QT intervals during early exercise were similar in patients without EIVA, irrespective of the presence or absence of CAD; however resting QTc was significantly longer in CAD patients who showed EIVA (443 +/- 40 ms; P less than 0.01) than in CAD patients without EIVA (424 +/- 37 ms) and in OV patients (421 +/- 32 ms). During early exercise, the QT interval remained significantly longer in patients with than in those without EIVA. There was a trend toward increasing resting QTc in patients who exhibited EIVA more severe than grade 3. When resting QTc was longer than 440 ms, subsequent EIVA were correctly predicted in CAD patients with a sensitivity of 43%, a specificity of 72% and a predictive accuracy of 63%. Thus, a trend toward longer resting QTc values exists in CAD patients who develop EIVA; however, a long resting QTc (greater than 440 ms) appears to be only a weak predictor of subsequent EIVA.

Adult↗

[Efficacy of diltiazem in elderly patients with stable effort angina].

The antianginal effects of 360 mg/day of diltiazem were evaluated, using intrapatient comparisons, in a double/blind, randomized, placebo/controlled trial in 24 young patients (50 +/- 7 years) and in 16 elderly patients (67 +/- 3 years) with stable effort angina. All patients had angiographic documentation of significant coronary artery disease. An open-labelled, randomized, crossover design was employed. For 1 week prior to beginning the study, the patient was on no medication except sublingual nitrates. The study consisted of an initial 2-week single-blind placebo run-in period followed by a 4-week randomized double-blind crossover between diltiazem, 120 mg t.i.d., and placebo. A diary of chest pain and nitroglycerin usage was kept during this period and run-in. Exercise tests were carried out during the run-in period (2 tests) and at the end of the 4-week treatment. After diltiazem 12 of the 24 young patients stopped the exercise test because of angina. A similar number (9/16) of elderly patients stopped the exercise test because of angina. During diltiazem treatment, weekly angina frequency was significantly reduced in the young patients (1.25 +/- 0.67 vs 3.87 +/- 1.19-run-in, 4.08 +/- 1.24-placebo; p less than 0.01) and in the elderly patients (0.87 +/- 0.71 vs 4.06 +/- 1.48-run-in, 4.12 +/- 1.5-placebo; p less than 0.01). Weekly TNT consumption significantly decreased in both groups of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗